STD, Sch40 Elbow Carbon Steel 45 Degree Elbow Executive standard number HG/T21635-1987

Carbon steel elbow

Carbon steel elbow can be divided into long radius elbow and short radius elbow according to its curvature radius. A long radius elbow is the outer diameter of a pipe whose curvature radius is equal to 1.5 times, that is, R = 1.5D. Short radius elbow means that its curvature radius is equal to the outside diameter of the pipe, that is, R = 1.0D. (D is the diameter of elbow, R is the radius of curvature. D can also be expressed in multiples. There are about seventeen kinds of pipe standards, which are the same as those in the United States. They are: Sch5s, Sch10s, Sch10, Sch20, Sch30, Sch40s, STD, Sch40, Sch60, Sch80s, XS; Sch80, Sch100, Sch120, Sch140, Sch160, XXS, among which STD and XS are the most commonly used. 

Angle 

there are 45 degree elbow, 90 degree elbow and 180 degree elbow. 

The implementation standards include GB/T 12459-2005, GB/T 13401-2005, GB/T 10752-1995, HG/T 21635-1987, D-GD0219, etc.